Magnet's attraction force on a piece of iron

[guideonl]

Hi everyone,
Please describe the process accures when placing an iron piece in front of (north pole) natural magnet bar, and how the attraction force is created.
Also, to calculate the force magnitude (coulomb law for magnetism formula) how can I determine the piece of iron pole intesity (m) after it became a magnet itself? (I assume that pole intensity (m) of bar magnet is known or could be detemine by neutral points experiment & measuring)
Thank you all

 

[phinds]

What research have you done on this so far? What have you found out?